PhD in Circular fuel supply for air transport via negative emission Hydrothermal Liquefaction (CIRCULAIR)

Jun 15, 2023 21:59:00 GMT+00:00
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Applicants are invited for a PhD fellowship/scholarship at Graduate School of Technical Sciences, Aarhus University, Denmark, within the Biological and Chemical Engineering programme. The position is available from 1 September 2023 or later.  

Title: Circular fuel supply for air transport via negative emission Hydrothermal Liquefaction (CIRCULAIR)

Research area and project description: Hydrothermal liquefaction (HTL) is a thermochemical processing technology that has been receiving increased interest for the production of sustainable aviation fuels from biomass. In a previous collaborative EU H2020 proeject ( we showed the feasibility of the process to produce fuels from agricultural residues, but we also found that the process water entails a large loss of carbon which is a burden to deal with.

The ambition of the follow up Horizon Europe project CIRCULAIR is to produce carbon negative aviation fuels from manure and straw. This is achieved by several innovations that will avoid carbon losses in the process chain to the product phases: process water, gas and hydrochar.

One of the main innovations is to clean the HTL process water by an exothermic process called wet oxidation (WO). The heat from WO can then be used to sustain both the WO itself as well as the main HTL process. This will solve the HTL process water challenge while allowing an autothermal integrated process. During the oxidation of the soluble organics in the process water, CO2 is formed which can be combined with the CO2 produced in the main HTL process. With the addition of green hydrogen from electrolysis this CO2 is converted to methanol to yield additional fuel for the shipping industry. By valorising all the process streams CIRULAIR aims to achieve a net negative process in terms of CO2 emissions.

The CIRCULAIR project has 10 partners from Italy, Spain, Denmark, Germany, France and Sweden, 7 academic and 3 industrial. The project will last for 4 years, starting 01.01.2023. It is a collaborative project so frequent exchange and collaboration with the other partners is essential.

The current PhD project has a key role in the overall CIRCULAIR process chain by investigating the wet oxidation process of HTL process waters in detail. The aim is to optimise the processing conditions of HTL and wet oxidation in order to provide sufficient heat to power both. This entails primarily experimental work in continuous flow reactors, some modelling aspects and heat exchanger design with the support from industrial partners. The industrial partner will construct an integration HTL-Wet oxidation reactor. Part of the PhD study is to operate this reactor and demonstrate the possibility of autothermal operation. The PhD student will also evaluate the gas phase for subsequent utilisation for methanol synthesis; how the gas phase is affected by varying process parameters and what cleaning steps may be required.

The PhD project will be divided in the following preliminary objectives:

1. Optimisation of wet oxidation process conditions for heat integration with HTL 

2. Demonstration of autothermal integrated HTL-Wet oxidation process

3. Optimization and preparation of HTL-WO gas phase for methanol synthesis.

For technical reasons, you must upload a project description. Please simply copy the project description above and upload it as a PDF in the application.  

Qualifications and specific competences: Applicants to the PhD position must have a recent, relevant Master’s degree (120 ECTS e.g. Chemical Engineering).

Prior experience operating chemical engineering laboratory equipment is desired. Knowledge on thermochemical processing technologies for biomass and/or hydrothermal liquefaction is an advantage.

The successful candidate has demonstrated excellent academic results. The ideal person has good collaboration skills and is also able to work independently.

Place of employment and place of work: The place of employment is Aarhus University, and the place of work is Hangøvej 2, 8200 Aarhus N

Contacts: Applicants seeking further information are invited to contact:

How to apply: Please follow this link to submit your application. Application deadline is 15 June 2023 at 23:59 CEST. Preferred starting date is 1 September 2023.

For information about application requirements and mandatory attachments, please see our application guide.

Please note:

  • The programme committee may request further information or invite the applicant to attend an interview.
  • Shortlisting will be used, which means that the evaluation committee only will evaluate the most relevant applications.

Aarhus University’s ambition is to be an attractive and inspiring workplace for all and to foster a culture in which each individual has opportunities to thrive, achieve and develop. We view equality and diversity as assets, and we welcome all applicants. All interested candidates are encouraged to apply, regardless of their personal background. Salary and terms of employment are in accordance with applicable collective agreement.